Climate Change Impact on Irrigation Water Requirement in Barito Kuala, South Kalimantan, Indonesia

Indonesia is the most populous country with more than 265 million people in 2018. Food security is persistent challenges, and the country`s levels are seriously high. Now the world must face climate change conditions. The important impacts of climate change on agricultural production and productivity in Indonesia are compounded by increasing urbanization that has a significant impact on agricultural land and increased pressure on scarce water resources. Rice production will continue to decrease in Java Island, in future so that Indonesia has to expand to other islands such as Kalimantan. Barito Kuala district is located in South Kalimantan and the coast of Barito River. Evapotranspiration is an important component of a hydrological cycle and the largest source of water loss, as well as for agricultural water requirements. The crop water requirements for water irrigation practices and efficient use of water. This study`s objective is to predict Barito Kuala`s water requirements for rice under the climate change scenario. First is to analyze the rainfall pattern and temperature using statistical methods, linear regression with daily observed data for 30 years. Second, the reference evapotranspiration (ETo) was computed using the Penman-Monteith method. Third, climate change scenario using the CMIP5 with the daily historical simulations over the period 1981–2009, and future projection series of the periods 2050s and 2090s. The result of this study shows impact of climate change on water requirement due to evapotranspiration value for deciding related to irrigation water resources management in Barito Kuala, South Kalimantan

Keywords: Barito Kuala, Climate Change, Lowland, Tidal Irrigation, Water Requirement